Spray nozzle unit

ABSTRACT

The invention relates to a spray nozzle unit, in particular for spraying explosion risk areas in subsurface mining, and for use in ultra high speed fire suppression system at response times below 50 milliseconds, having a nozzle body. The nozzle body has a nozzle opening for ejecting spray liquid, allowing low water consumption, designed robustly, and allowing operation without compressed air. A closing means is disposed in the nozzle body for closing the nozzle opening in the non-pressurized state of the spray nozzle unit.

The present invention proposes a spray nozzle unit for spraying heavilydust-laden areas as well as potentially explosive areas in undergroundmining, with a nozzle body that exhibits a nozzle opening for ejectingspray liquid.

PRIOR ART

Various methods are used for finely spraying liquids at a low waterconsumption level.

1. Fine spray nozzles with very small bore diameters, e.g., 1 mm, whichare operated at high pressures ranging between 50 and 200 bar.

2. Two-component nozzles that use compressed air to finely atomize theliquids.

The disadvantages include a potential jamming of nozzles on the onehand, and the necessity for compressed air on the other, which areassociated with significant drawbacks, in particular in undergroundmining.

Known from DE 198 51 620 A1 is a generic spray nozzle unit. Spray nozzleunits are used in particular for spraying potentially explosive areas inunderground mining, and a plurality of spray nozzle units can beaccommodated on a nozzle receptacle of a spraying system, for example soas to spray the cutting area of the selective cut heading machine withwater underground. In order to spray the cutting area as comprehensivelyas possible, it can be provided that highly pressurized compressed airbe added to the supplied water to ensure that the water is effectivelyatomized, wherein the necessary water consumption is reduced at the sametime. However, the disadvantage to using atomizing nozzles is thatcompressed air with high pressure values must be provided to atomize theadded water.

By contrast, spray nozzle units that do not need compressed air and areoperated at high water pressures lead to high water consumption. If thediameter of the nozzle opening is diminished to reduce waterconsumption, a high water pressure is necessary, which requires anintricate process to prepare.

Given the harsh conditions under which such spray nozzle units are usedunderground, in particular in direct proximity to the cutting area of aselective cut heading machine, the spray nozzle unit must be furnishedwith an appropriately robust design. Contaminants can penetrate into thenozzle opening and end up jamming the spray nozzle unit, so that thecutting area of a selective cut heading machine might no longer bereliably sprayed. The machine operator is basically unable to see thearea in which the spray nozzle units are arranged in a nozzle receptacleof a spraying system. This makes it difficult to oversee the process ofmonitoring a spraying system to verify smooth operation. Therefore, anozzle unit having an especially robust design is desirable.

OBJECT OF THE INVENTION

As a consequence, the object of the present invention is to provide aspray nozzle unit that overcomes the disadvantages to the prior artdescribed above, and enables low water consumption. Further, the objectof the present invention is to provide a spray nozzle unit having arobust design. Finally, the object of the present invention is toprovide a spray nozzle unit with a low water consumption that enablescompressed air-free operation, and is suitable for use in ultra highspeed fire suppression systems at response times of below 50milliseconds.

This object is achieved based on a spray nozzle unit according to thepreamble to claim 1 in conjunction with its characterizing features.Practical further developments of the invention are indicated in thedependent claims.

DISCLOSURE OF THE INVENTION

The invention encompasses the technical instruction that the nozzle bodyincorporates a closing means that closes the nozzle opening with thespray nozzle unit in an unpressurized state.

The advantage achieved by arranging a closing means in the nozzle bodyis that the nozzle opening can then be closed by the closing means whenthe spray nozzle unit is not in operation, i.e., the spray nozzle unitis not pressurized, and thus at zero pressure. No contaminants can getinto the nozzle opening with the spray nozzle unit operational, sincethe exiting spray liquid, in particular water, prevents contaminantsfrom penetrating into the nozzle opening. If the spray nozzle unit isnot operational, the closing means according to the invention preventscontaminants from entering the nozzle opening. As a result, contaminantsare prevented from penetrating into the nozzle opening, regardless ofthe operating state of the spray nozzle unit. Arranging the closingmeans in the nozzle body itself protects the closing means againstmechanical influences, and the nozzle body of the spray nozzle unit canbe given the conventional outside design.

It is especially advantageous that the closing means be designed as aclamping piston, which preferably is reciprocatingly incorporated in thenozzle body along a central axis of the nozzle body. The nozzle body canessentially have a rotationally symmetrical configuration, basicallygiving it roughly cylindrical shape. The rotational axis of thecylindrical nozzle body forms the central axis, wherein the clampingpiston is also rotationally symmetrical. As a consequence, the clampingpiston can be guided back and forth between a closed position and openposition along the central axis, wherein the clamping piston closes thenozzle opening in the closed position, and releases it in the openposition.

It is especially advantageous that the closing means be able toreciprocate between a closed position and open position along thecentral axis by pressurizing the spray nozzle unit with spray liquid.Pressurization with the spray liquid takes place in such a way that theclosing means can be moved from the open position to the closedposition. Once pressurization has ended, the closing means moves backinto the closed position from the open position. As a consequence,neither a manually activated closing means nor an actuator is needed,since the closing means is advantageously arranged in the nozzle body insuch a way that the reciprocating motion is caused solely bypressurization with the spray liquid.

The closing means advantageously exhibits a locking pin for at leastpartial immersion into the nozzle opening in its closed position. Thelocking pin can preferably exhibit an outer diameter roughlycorresponding to the inner diameter of the nozzle opening. Therefore,the locking pin forms an extension on the closing means, and is alsorotationally symmetrically arranged around the central axis of thenozzle body. If the closing means is moved toward the closed position,the locking pin dips into the nozzle opening, wherein the immersiondepth preferably corresponds to at least the length of the nozzleopening toward the central axis. This reliably prevents contaminants,such as dust, cave material and the like from being able to get into thenozzle opening. The locking pin preferably exhibits a length at whichthe locking pin extends completely through the nozzle opening in theclosed position, in particular closing off the nozzle body from outside.

It is further advantageous for the nozzle body to incorporate a pressurechamber movably bordered by the closing means. The pressure chamber canbe pressurized with spray liquid, wherein the pressure chamber ispreferably arranged in such a way that the closing means can be movedfrom the closed position to the open position by pressurizing thepressure chamber.

Having a partial area of the closing means movably border the pressurechamber causes the closing means to move in the nozzle body in such away that the pressure chamber volume increases. As a result, the closingmeans can get from the closed position into the open position. It isfurther advantageous for the closing means designed as a clamping pistonto exhibit at least one sealing element to make the pressure chamberpressure-tight. In particular, the sealing element dynamically seals theclamping piston against the interior wall of the nozzle body.

It is further advantageous to provide a spring element that springpreloads the closing means in the closed position. If the spray nozzleunit is not pressurized with spray liquid, it must be ensured that theclosing means stays in the closed position. Only then does the lockingpin extend through the nozzle opening, and contaminants are effectivelyprevented from penetrating into the nozzle opening. The spring elementis preferably designed as a helical compression spring, and located on aside of the closing means opposite the arrangement of the pressurechamber bordering the closing means.

In another advantageous embodiment of the spray nozzle unit according tothe invention, the closing means exhibits a feed channel through whichthe pressure chamber can be pressurized with spray liquid. The feedchannel extends from one receiving side of the nozzle body until intothe pressure chamber. At the same time, the receiving side of the nozzlebody forms the side on which the spray nozzle unit is supplied withspray liquid, in particular water. As an alternative, the feed channelcan also extend through the nozzle body in order to expose the pressurechamber to spray liquid.

The pressure chamber is advantageously fluidically connected with thenozzle opening, in particular when the closing means is released fromthe closed position. The spray liquid provided via the feed channelinitially floods the pressure chamber, before the spray liquid gets fromthe pressure chamber into the nozzle opening, to then exit the spraynozzle unit again via the spray side of the nozzle body. As aconsequence, the spray liquid is first used to move the closing meansinto the open position or keep the closing means in the open position,so as to then exit the spray nozzle unit via the nozzle opening foratomization. If the closing means is still in the closed position, thepressure chamber already has a starting volume. If the pressure chamberis pressurized with the closing means in the closed state, the pressureacts on the wall of the closing means bordering the pressure chamber, sothat the closing means moves from the closed position into the openposition. While the spray nozzle unit is in operation, the pressure ofthe spray liquid prevailing in the pressure chamber is high enough tokeep the closing means in the open position.

It is basically possible to have the pressure chamber supplied only viaa bypass, so that a portion, in particular most, of the spray liquidgets into the nozzle opening through the closing means via a primarychannel. The portion of spray liquid passing into the pressure chambervia a bypass can be calculated in such a way that also makes it possibleto keep the closing means in the open position.

In addition, the nozzle body can incorporate a low-pressure chambermovably bordered by the closing means on a side lying opposite thepressure chamber. Preferably situated in the nozzle body is a vent portthat links the low-pressure chamber with the outside of the nozzle body.The vent port allows the low-pressure chamber to breathe, and when theclosing means moves from the closed position into the open position, aircan escape to the outside from the low-pressure chamber through the ventport. As the closing means moves back into the closed position, airflows through the vent port and back into the low-pressure chamber. Inparticular, the spring element can be situated in the low-pressurechamber to preload the closing means toward the closed position.

In another advantageous embodiment of the spray nozzle unit according tothe invention, the pressure chamber empties like a funnel into thenozzle opening with the closing means in the open position, wherein thesurfaces bordering the pressure chamber at least partially exhibit ahelical structure that allows the spray liquid to exit the nozzleopening with an angular momentum. The surfaces of the helical structureinvolve in particular the surfaces adjacent to the nozzle opening, forexample inside the nozzle body and/or at the front of the closing means.This causes the spray liquid to helically move around the central axis,so that the spray liquid can exit the nozzle opening with an angularmomentum. As a result, an especially large spraying angle can beachieved, at which the spray liquid exits the nozzle opening. In afurther advantage, the feed channel can empty into the pressure chamberin such a way as to already generate a rotation by the spray liquidaround the central axis. The pressure chamber also extends around thecentral axis in a rotationally symmetrical manner, and a flow crosssection tapering like a funnel toward the nozzle opening serves tointensify the twisting effect. As a result, a comparably large diameterof the nozzle opening can be used to finely atomize the spray liquid, inparticular into small water droplets. The fluid pressure of the sprayliquid can measure 4 bar to 8 bar, preferably 5 bar to 7 bar, andespecially preferably 6 bar. A water system with 6 bar is routinelyencountered in underground mining, so that no peripheral equipment mustbe provided to operate a spraying system at higher pressures.

It is especially advantageous for the nozzle opening to exhibit adiameter of 1 mm to 6 mm, preferably a diameter of 2 mm to 4 mm, andespecially preferably a diameter of 3 mm. In particular, the locking pincan be situated adjacent to the nozzle opening in the open position. Asa consequence, the locking pin can also extend at least partially intothe nozzle opening with the closing means in the open position. Anannular cross section can be formed in this way, as a result of whichthe spray liquid can be made to exit as a solid jet or even a hollow jet(the generation of a solid jet must here be regarded as an innovation).If a centrally present locking pin brings about an annular cross sectionin the nozzle opening, a hollow jet of spray liquid can be generated. Inorder to close the nozzle opening, the locking pin can be introduced sofar into the nozzle opening that the latter completely runs through thenozzle opening. In particular, the locking pin can be designed withincremental diameters, so as to also ensure the closure of the nozzleopening to prevent contaminants from penetrating, while on the otherhand, a hollow jet of spray liquid can be prepared with the closingmeans in the open position If a smaller incremental diameter extendsinto the nozzle opening as well.

It is further advantageous for the closing means to exhibit a headsection, which is designed to create a solid jet spray or hollow jetspray, and in particular is replaceably arranged on the closing means.As an alternative, the entire closing means can be replaceablyincorporated in the nozzle body. The locking pin is situated on the headsection, so that replacing the head section makes it possible to changeout the locking pin on the closing means at the same time. As aconsequence, the spray nozzle unit can be configured with a nozzleopening-locking pin arrangement, depending on the operating conditions,so that a solid jet or hollow jet of spray liquid are alternately madeavailable. This preferably takes place at low k-values for the nozzle,for example of about 1.2 (nozzle opening diameter: 3 mm). This ensureslow water consumption at a comparatively large nozzle opening diameter.

It is further advantageous for the nozzle body to be configured forarrangement in a nozzle receptacle of a spraying system that serves inparticular to spray a cutting head of a selective cut heading machine inunderground mining. In order to arrange the nozzle body in a nozzlereceptacle, the latter can exhibit a threaded section with which thenozzle body can be screwed into a nozzle receptacle. For purposes ofscrewing in, the nozzle body can further exhibit a wrench geometry, soas to screw the nozzle body into the nozzle receptacle via the threadedsection using a tool.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional measures that improve the invention will be described ingreater detail in conjunction with the specification using preferredexemplary embodiments of the invention based on the figures. Shownpurely schematically on:

FIG. 1 is an exemplary embodiment of a spray nozzle unit with a closingmeans according to the invention in an open position;

FIG. 2 is an exemplary embodiment of the spray nozzle unit with aclosing means according to the invention in a closed position;

FIG. 3 is another exemplary embodiment of a spray nozzle unit with aclosing means according to the invention in a closed position;

FIG. 4 is another exemplary embodiment of the spray nozzle unit with aclosing means according to the invention in an open position;

FIG. 5 is the other exemplary embodiment according to FIG. 3 and FIG. 4in an exploded view.

PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 shows an exemplary embodiment of a spray nozzle unit 100 of thekind that can be used for spraying potentially explosive areas inunderground mining. The spray nozzle unit 100 can be placed in a nozzlereceptacle of a spraying system, which is used in particular to spray acutting head of a selective cut heading machine in underground mining.

The spray nozzle unit 100 exhibits a nozzle body 10 that extendsrotationally symmetrically around a central axis 13. In order to screwin the nozzle body 10, for example into a nozzle receptacle of aspraying system, the nozzle body 10 is provided with a threaded section19. In order to screw the nozzle body 10 into the nozzle receptacle witha tool, the outside of the nozzle body 10 exhibits a wrench geometry 20,for example so as to screw in the nozzle body 10 with an open-endwrench, a box wrench, a spanner wrench or the like. The nozzle bodyexhibits roughly a cylindrical shape, and extends along the central axis13, from a receiving side 10 a to a spray side 10 b. If the nozzle body10 is placed in a nozzle receptacle of a spraying system, a waterpressure prevails on the receiving side 10 a, and the water present onthe receiving side 10 a can make its way through the nozzle body 10 andbe sprayed on the spray side 10 b. To this end, the spray side 10 b ofthe nozzle body 10 exhibits a nozzle opening 11, through which the waterexits toward the area to be sprayed.

According to the present invention, a closing means 12 is arranged inthe nozzle body 10. The closing means 12 is designed as a clampingpiston 12, and accommodated along the central axis 13 so that it canmove back and forth between a closed position and the depicted openposition. The clamping piston 12 is longitudinally guided in the nozzlebody 10, and sealed against the inner wall of the nozzle body 10 with asealing element 22. The receiving side 10 a of the nozzle body 10exhibits an insert element 21, in which the clamping piston 12 is alsoguided along the central axis 13 and sealed with another sealing element23.

A feed channel 16 exhibiting a first feed channel section 16 a and atleast two second feed channel sections 16 b extends through the clampingpiston 12. The pressurized water coming from the receiving side 10 a isrouted through the feed channel 16 a and into the feed port 16. Thewater supply is denoted with an arrow 24. The water passes through afilter 25, for example situated on the rear of the insert element 21 ofthe nozzle body 10.

The water passes through the first feed channel section 16 a and thesecond feed channel sections 16 b, and enters a pressure chamber 14inside the nozzle body 10. The pressure chamber 14 is moveably borderedby the clamping piston 12. The water pressure present in the pressurechamber 14, for example at 4 bar, or preferably at 6 bar, moves theclamping piston 12 into the depicted open position. At the same time, alocking pin 12 a present on the front of the clamping piston 12 releasesthe nozzle opening 11.

The movement of the clamping piston 12 toward the depicted open positiontakes place against the preloaded force exerted by a spring element 15.The latter is located on the side of the clamping piston 12 lyingopposite the arrangement of the pressure chamber 14. As a consequence,the spring element 15 preloads the clamping piston 12 in the closingdirection, in which the locking pin 12 a extends through the nozzleopening 11. This prevents contaminants from being able to get into thenozzle opening 11 in the resting state. For example, the spring element15 is designed as a helical compression spring, and is clamped betweenthe insert element 21 and a collar of the clamping piston 12. As long aswater supply 24 is ongoing, and as long as the pressure chamber 14 isthus pressurized, the clamping piston 12 remains in the depicted openposition, and the water can exit the nozzle opening 12 as illustrated.

The pressure chamber 14 empties like a funnel into the nozzle opening 11when the clamping piston 12 is in the open position, wherein thesurfaces bordering the pressure chamber 14 exhibit a helical structure,which causes the water to exit the nozzle opening 11 with an angularmomentum. This yields a large spraying angle, for example a sprayingangle of 90°. Since the pressure chamber 14 extends rotationallysymmetrically around the clamping piston 12 and the locking pin 12 a,the twisting effect of the water exiting the nozzle opening 11 isfurther intensified. In the position shown behind the nozzle opening 11,the locking pin 12 a can preferably be arranged inside the nozzle body10 with the clamping piston 12 in the open position. In particular, itis possible to geometrically design the clamping piston 12 with thelocking pin 12 a and nozzle body 10 with the nozzle opening 11 in such away as to have a small distance between the locking pin 12 a and nozzleopening 11, so as to elevate the twisting effect of the exiting water.In particular, the water can as a result exit the nozzle opening 11 in ahollow jet, e.g., to achieve a k-value for the nozzle unit 100 of 1.2(fluid pressure 6 bar, nozzle opening diameter 3 mm), for example.

A low-pressure chamber 17 is formed in the nozzle body 10 on the side ofthe clamping piston 12 facing away from the pressure chamber 14. A ventport 18 fluidically connects the low-pressure chamber 17 with theoutside of the nozzle body 10. If the clamping piston 12 moves betweenthe closed position and open position, the volume of the low-pressurechamber 17 changes, and the vent port 18 allows it to breathe. Accordingto the depiction, the spring element 15 is arranged inside thelow-pressure chamber 17.

FIG. 2 presents another view of the exemplary embodiment of the spraynozzle unit 100 according to FIG. 1. According to the depiction, theclamping piston 12 is situated in the closed position. In thisarrangement, the locking pin 12 a extends through the nozzle opening 11.The clamping piston 12 assumes the shown position inside the nozzle body10 if no water is supplied via the receiving side 10 a of the spraynozzle unit 100. Arranging the clamping piston 12 a in the closedposition diminishes the volume of the pressure chamber 14, and raisesthe volume out of the low-pressure chamber 17. As a consequence,compensating air streams through the vent port 18 into the low-pressurechamber 17. Also discernible is a geometric configuration of theclamping piston 12 allowing the rear clamping piston section 12 to beguided in the insert element 21. The sealing element 23 also ensuresthat the low-pressure chamber 17 is sealed against water pressure on thereceiving side 10 a of the spray nozzle unit 100. If the receiving side10 a is again pressurized, the water in turn passes through the supplychannel 16 and into the pressure chamber 14, and the clamping piston 12is moved to the open position against the force exerted by the springelement 15.

Another exemplary embodiment is depicted on FIGS. 3, 4 and 5. The samereference numbers here denote the same parts as in the first exemplaryembodiment. The difference relative to the initially described spraynozzle unit is that the nozzle body 10 here consists of a nozzleconnecting part 10 c and a main nozzle part 10 d. The latter are joinedtogether by a bore ring (spring ring) 26. The nozzle opening 11 throughwhich the clamping piston 12 extends is formed in the main nozzle part10 d. The latter also passes through a helical body 27, which comprisesthe closing means 12, and exhibits a circumferential groove 29 on itsconical sealing surface 28 for accommodating the nozzle seal (O-ring)30. The clamping piston 12 is arranged on a nozzle piston 31, whichexhibits a guide section 34 whose exterior exhibits a circumferentialgroove 35 for accommodating the piston seal (O-ring) 36. The guidesection 34 is made to abut the nozzle connecting part 10 c via thecompression spring 15. The locking pin 31 c is situated on the guidesection 34 as the closing means via a retaining bolt 31 b. After screwedin, the nozzle connecting part 10 c is sealed against the main nozzlepart 10 d by the additional piston ring (O-ring) 36. The relief hole isno longer required in this embodiment. The clearances between theindividual bodies allows air to escape into the intermediate chamber 37.After installation, the nozzle body 10 can no longer be opened, at leastnot non-destructively. Dividing the nozzle body 10 into the nozzleconnecting part 10 c and main nozzle part 10 d provides a range ofvarious possible connections to choose from without having to alter thenozzle components. The exemplary embodiment selected presents a screwedconnection of the nozzle connecting part 10 c and main nozzle part 10 d.Any type of threads can here be used. The division into two parts alsomakes it possible to turn or tighten the main nozzle part 10 dindependently of the nozzle connecting part 10 c. This configuration isespecially important when the nozzle has to be hooked up to piping orsilo walls, and must remain outwardly tightly sealed (e.g., due to therisk of explosion). In prior art, a screw joint had to be incorporatedbetween the nozzle and piping, so that both ends could be screwedtogether tightly.

The insert part of the nozzle body 10 is protected against contaminantsin area 10 a by a sieve 38. The sieve 38 is fixed in place by a borering 39, so that too strong a flow cannot tear it away.

The closing means 12 exhibits a helical body 27, the cross section ofwhich is shown in detail A. Changing the channels 40 in the helical body27, e.g., the number, position relative to center of gravity, depth andwidth, makes it possible to achieve variations in terms of the dropletsize, spray angle (jet cone) and flow rate (K value variations), withouthaving to change the other components in any way.

As already described above, the closing means 12 is provided with anozzle seal (O-ring) 30 in this embodiment. Given a drop in pressurewhen the water supply is stopped, this O-ring makes it possible to keepthe nozzle body 10 sealed to the outside, i.e., the extinguishing wateronly reaches as far as the nozzle outlet opening 11 closed by theclamping piston, and the nozzle line (not shown) also remains filledwith water. This characteristic is very important in extinguishingsystems, where very rapid opening times are crucial. Because theextinguisher supply lines are always filled with water, virtually nodelay is to be expected in triggering the extinguishing system.Introducing the seal 30 in a circumferential groove 29 in the conicalsealing surface 28 produces no additional delays in opening the nozzle,since there is no vertical travel.

It is very especially advantageous that the nozzle body 10 be heldtightly even to the outside by the locking piece 27 or pressure hull 27while interacting with the seal 30 designed as an O-ring and exposed tothe resilient force F exerted by the compression spring 15. Theresilient force F of the compression spring 15 acting on the nozzlepiston 31 presses the seal 30 of the helical body 27 against theinterior wall of the main nozzle part 10 d, thereby preserving the seal.Selecting various spring configurations or various spring rates alsomakes it possible to determine the residual pressure in the extinguisherwater supply line and change it as desired.

The invention is not limited in its configuration to the preferredexemplary embodiments indicated above.

Rather, a number of variants are conceivable, which make use of thedescribed solution even given embodiments that are different. Allfeatures and/or advantages arising from the claims, specification ordrawings, including structural details, spatial arrangements andprocedural steps, can be essential to the invention both takenseparately and in the most varied of combinations.

REFERENCE LIST

-   100 Spray nozzle unit-   10 Nozzle body-   10 a Area/receiving side-   10 b Spray side-   10 c Nozzle connecting part-   10 d Main nozzle part-   11 Nozzle opening-   12 Closing means, clamping piston-   12 a Locking pin-   12 b Head section-   13 Central axis-   14 Pressure chamber-   15 Spring element-   16 Feed channel-   16 a First feed channel section-   16 b Second feed channel section-   17 Low-pressure chamber-   18 Vent port-   19 Threaded section-   20 Wrench geometry-   21 Insert element-   22 Sealing element-   23 Sealing element-   24 Water supply-   25 Filter-   26 Bore ring (spring ring)-   27 Helical body-   28 Sealing surface-   29 Circumferential groove-   30 Nozzle seal (O-ring)-   31 Nozzle piston-   34 Guide section-   35 Circumferential groove-   36 Piston seal (0-ring)-   37 Intermediate chamber-   38 Sieve-   39 Bore ring-   40 Channels-   F Spring force

1. A spray nozzle unit for spraying potentially explosive areas inunderground mining, comprising a nozzle body that has a nozzle openingfor ejecting spray liquid, wherein in that the nozzle body incorporatesa closing means that closes the nozzle opening with the spray nozzleunit in an unpressurized state.
 2. The spray nozzle according to claim1, wherein the closing means is designed as a clamping piston, which isreciprocatingly incorporated in the nozzle body along a central axis ofthe nozzle body.
 3. The spray nozzle according to claim 2, wherein theclosing means is able to reciprocate between a closed position and anopen position along the central axis by pressurizing the spray nozzleunit with spray liquid.
 4. The spray nozzle according to claim 3,wherein the closing means has a locking pin for at least partialimmersion into the nozzle opening in its closed position.
 5. The spraynozzle according to one of the aforementioned claims, wherein the nozzlebody includes a pressure chamber movably bordered by the closing means.6. The spray nozzle according to claim 5, wherein the pressure chambercan be pressurized with spray liquid, wherein the pressure chamber ispreferably arranged in such a way that the closing means can be movedfrom the closed position to the open position by pressurizing thepressure chamber.
 7. The spray nozzle according to claim 3, wherein aspring element is provided that preloads the closing means in the closedposition.
 8. The spray nozzle according to claim 6, wherein the closingmeans exhibits a feed channel through which the pressure chamber can bepressurized with spray liquid.
 9. The spray nozzle according to claim 6,wherein the pressure chamber is fluidically connected with the nozzleopening when the closing means is released from the closed position. 10.The spray nozzle according to claim 5, wherein the nozzle furtherincludes a low-pressure chamber that is movably bordered by the closingmeans on a side lying opposite the pressure chamber.
 11. The spraynozzle according to claim 10, wherein a vent port that links thelow-pressure chamber with the outside of the nozzle body is situated inthe nozzle body.
 12. The spray nozzle according to claim 5, wherein thepressure chamber empties like a funnel into the nozzle opening with theclosing means in the open position, wherein the surfaces bordering thepressure chamber at least partially exhibit a helical structure thatallows the spray liquid to exit the nozzle opening with an angularmomentum.
 13. The spray nozzle according to claim 12, wherein the nozzleopening has a diameter of 1 mm to 6 mm.
 14. The spray nozzle accordingto any one of claims 1-4, wherein the closing means has a head section,which is designed to create a solid jet spray or hollow jet spray, andis replaceably arranged on the closing means.
 15. The spray nozzleaccording to any one of claims 1-4 or 7, wherein the nozzle body isconfigured for arrangement in a nozzle receptacle of a spraying systemthat serves to spray a cutting head of a selective cut heading machinein underground mining.
 16. The spray nozzle according to any one ofclaims 1-4 or 7, wherein the nozzle body comprises a nozzle connectingpart and a main nozzle body, which are detachable or undetachable indesign.
 17. The spray nozzle according to any one of claims 1-4 or 7,wherein the nozzle body has a helical body, which comprises the closingmeans and has channels to adjust the droplet size, spray angle and flowrate of the spray nozzle unit.
 18. The spray nozzle according to claim17, wherein the helical body has a conical sealing surface, whichcircumferentially incorporates a groove that accommodates an O-ringseal.